Comparative performance of liquid chromatography and spectrophotometry in determining metformin hydrochloride within pharmaceutical formulations

The present study compared the performance of Ultra-high performance liquid chromatography (UHPLC) and UV-Vis spectrophotometry for the quantification of metformin hydrochloride in five commercially available metformin hydrochloride products with different strengths. The metformin hydrochloride was measured in the UHPLC with a mobile phase consisting of a mixture of 0.05 M phosphate buffer solution and methanol (35:65, v/v) with a pH of 3.6. Metformin hydrochloride was determined spectrophotometrically at 234 nm using a mixture of methanol and water as a blank. The methods' linearity for metformin hydrochloride was within the concentration range of (2.5-40 μg/ml) in both techniques. The validation process encompassed assessments of specificity, selectivity, linearity, accuracy, precision, the lower limit of quantification (LLOQ), the lower limit of detection (LLOD), robustness, and system suitability. For the UHPLC validation method, the repeatability and reproducibility (expressed as relative standard deviation) were less than 1.578 and 2.718 %, respectively. The LLOQ for metformin hydrochloride was 0.625 μg/ml, and the LLOD was 0.156 μg/ml. For the UV-Vis spectrophotometric validation method, the repeatability and reproducibility (stated as relative standard deviation) were less than 3.773 and 1.988 %, respectively. The percentage recovery results for the five brands of metformin hydrochloride tablets were (98-101 %) and (92-104 %) for the UHPLC and UV-Vis spectrophotometric methods, respectively. In conclusion, the described methodologies were successfully employed for the quantitative analysis of metformin hydrochloride in different pharmaceutical tablet products.